Front-mounted power control unit for bulldozer



May 1, 1962 3,031,779

FRONT-MOUNTED POWER CONTROL UNIT FOR BULL-DOZER Filed June 12, 1958 J.M. GWlNN, JR.. ETAL '7 Sheets-Sheet l z swam m2. 3. M PM W6 J fig W 1 25V May 1962 J. M. GWINN, JR., ETAL 3,031,779

FRONT-MOUNTED POWER CONTROL UNIT FOR BULLDOZER Filed June 12, 1958 7Sheds-Sheet 2 May 1, 1962 .1. M. GWINN, JR., ETAL 3,031,779

FRONT-MOUNTED POWER CONTROL UNIT FOR BULLDOZER Filed June 12, 1958 '7Sheets-Sheet 3 5 NVENTORS Ja'cp/z E 57,4; .x 037.18,,

y 1962 J. M. GWINN, JR., ETAL 3,031,779

FRONT-MOUNTED POWER CONTROL UNIT FOR BULLDOZER Filed June 12, 1958 TSheets-Sheet 4 INVENTORS. 7556p; M 6 301-7771,;

May 1, 1962 J. M. GWINN, JR.. ETAL 3,031,779

FRONT-MOUNTED POWER CONTROL UNIT FOR BULLDOZER '7- Sheets-Sheet 5 FiledJune 12, 1958 May 1, 1962 J. M. GWINN, JR., ETAL 3,031,779

FRONT-MOUNTED POWER CONTROL UNIT FOR BULLDOZER 7 Sheets-Sheen 6 FiledJune 12, 1958 n .p mm 7. w m P? in M FRONT-MOUNTED POWER CONTROL UNITFOR BULLDOZER Filed June 12, 1958 May 1, 1962 J. M. GWlNN, JR, ETAL 7Sheets-Sheet '7' (llllfl II I.

3,031,779 FRONT-MOUNTED PGWER CGNTRGL UNlT FOR BULLDOZER Joseph M.Gwinn, J12, Dcarhorn, and Angus J. GBrien,

Birmingham, Mich, and William R. Shireman, Findlay,

Ohio, assignors to Gar Wood industries, inc.

Filed June 12, 1958, er. No. 74l,7tl3 3 Claims. ((31. It'l -144) Thisinvention relates generally to tractors provided at one end with a dozerblade or the like and more particularly to a power control unit which ismounted on such a tractor for raising and lowering the dozer blade. Thisapplication is a continuation in part of my copending application SerialNo. 658,746, filed May 13, i957, now abandoned.

Commercial tractors of the kind used for earth moving and similaroperations are commonly provided with front end power control apparatusfor raising and lowering equipment mounted on the front end of thetractor. Such is the case with both the conventional single engintractors and the twin-type TC-l2 tractors manufactured by the EuclidDivision of Ge eral Motors Corporation of Detroit, Michigan, illustratedin the drawing. The power control apparatus includes either a cable andsheave-type power output or a hydraulic cylinder assembly type outputwhich are applied to the tractor e er in the field or at the factory. inthe past, such uni have consisted of a plurality of parts which must beseparately mounted on the tractor, usually at the factory by skilledtechnicians. Furthermore, by virtue of the construction of these priorunits, some of the parts have been located at lower positions on thetractor front end where they readily become jammed with rocks, dirt andthe like.

An object of this invention, therefore, is to provide an improved powercontrol unit which is readily applied to the front end of a tractoreither at the factory or in the field.

A further object of this invention is to provide a power control unitwhich is constructed so that when it is mounted on the tractorsubstantially all parts of the unit are at an elevated position on thetractor so as to be out of the path of rocks, dirt, and other materialwhich oftentimes pile up in the vicinity of the tractor front end whenthe tractor is used for dozing operations and the like.

Another object of this invention is to provide a front end housing ornose guard for a tractor which is adapted to support and house either awinch-type power transmission mechanism for a cable and sheave output ora pump, tank and valve mechanism for transmitting power to a hydrauliccylinder-type power output.

A further object of this invention is to provide a power transmissionunit for a cable and sheave-type output which is mounted as apre-assembled unit on the tractor by merely bolting a cover plate on theunit to a housing on the tractor.

A further object of this invention is to provide a unit for transmittingpower from the tractor engine to a hydraulic cyl nder-type power outputwhich unit is mounted as a pre-assemblcd package on the tractor bymerely bolting a cover plate on the unit to a housing on the tractor.

Still a further object of this invention is to provide a power controlunit which is relatively simple in construction, economical tomanufacture and efficient in operation in raising and lowering tractorfront end equipment.

Further objects, features and advantages of this invention will becomeapparent from a consideration of the following description, the appendedclaims and the accornpanying drawing in which:

FIG. 1 is a perspective View of a twin-type crawler assists tractorprovided with the form of the power control unit of this invention whichoperates a cable and sheave-type output;

FIG. 2 is a side elevational view of the tractor and power control unitshown in F1 8. 1;

3 is an enlarged sectional view looking substantially along the line 33in PEG. 1;

4 is a transverse sectional view looking along the line 44 in FIG. 3;

PEG. 5 is a sectional view looking along the line 55 in E56. 4 andillustrating a power transmission mecha- "ri for a cable and sheavepower output in the unit of this invention;

FIG. 6 is a diagrammatic view showing the cable arrangement in the unitshown in H6. 1;

Flt 7 is an enlarged elevational view of the sheave support illustratedin PEG. 2 on the rear side of the dozer blade;

PEG. 8 a fragmentary front elevational view of one of the control unithousings, with some parts broken away and other parts shown in sectionfor the purpose of illustrating the brake and clutch band operatingmechanism in the power transmission mechanism shown in are iragnzentarysectional views lookltl1i respectively in a foreshortened sideelevational View, illus 'ly to H6. 2, of a crawler tractor provided aform or the power control unit of this invention in which a hydrauliccylinder assembly type power output is utilized;

FIG. 12 is an enlarged fragmentary view looking substantially along theline iZ-ifz. in E6. ll;

FIG. 13 is a fragmentary elevational view, looking substantially alongthe line 13-13 in ll, of a portion of the structure which supports thehydraulic cylinder assembly in the unit shown in FIG. 11;

PEG. 14 is a transverse sectional view looking along the line i i-id inFIG. ll;

Fit}. l5 is a fragmentary side elevational view of the structure shownin FIG. 12; and

FlG. 16 is a fragmentary top plan view of a portion of the structureillustrated in FIG. 15, with some parts broken away and other partsshown in section for the purpose of clarity.

With reference to the drawing, one form of the power control unit ofthis invention, indicated generally at 26, is illustrated in FIG. Imounted on the front end of a TC- 12 crawler-type tractor 21. It is tobe understood, however, that the power control units of this inventionare equally adapted for any tractor and are shown and described Withrespect to the TC12 because it includes all of the elements of aconventional single engine tractor. As is well known, the twin-type oftractor consists of a pair of side-by-side sections 22 and 24, each ofwhich is provided with a main frame 26 which supports a radiator 27, atrack 28, and an engine 25? supported on a forward portion 26a of theframe 26. The frames 2s for the sections 22 and 24 are connected forlimited relative rotation about an axis extended transversely of thetractor and located approximately at the position indicated at 3%.

A dozer attachment, indicated generally at 32 is illustrated in FIGS. 1and 2 mounted on the tractor 22. The attachment 32 includes an uprightdozer blade 34, of usual type, supported on the front end of a pair ofarms 36 which are pivotally connected at their rear ends to oppositesides of the tractor Z1.

A pair of blade adjusting struts 37 and 3%, corresponding to the arms36, extend between the arms36 and the upper end of the blade 34. Thestrut 38 includes a manually adjustable pump and cylinder assembly it}for extending and retracting the strut 33 to adjust the inclination ofthe blade 34 transversely of the tractor 21.

The control unit 29 includes a pair of substantially identical housings42 and 44, corresponding to and mounted on the tractor sections 22 and24. Each housing 42 or 44 is mounted on the engine portion 260 of thecorresponding tractor frame section 26 forwardly of the correspondingengine 29. Each of the housings 42 and 44 includes a hollow main or rearpart 46 which has an open front end and is of a shape to conform to theoverall outline of the tractor 21 (FIG. 2) and provide the tractor withthe desired side silhouette. A pair of mounting plates 50 ontransversely opposite sides of each part 46 are connected to the tractorframe portions 26a and carry pairs of inwardly extending pins 51 whichfit in openings in the housing parts 46. As a result, either of thehousings is readily removed or installed as desired by merely pulling orinserting the pins 51 on the corresponding mounting plates 50.

Mounted on the upper end of each of the housing parts 46 is a sheavesupporting unit 52 releasably connected to the housing by means of bolts55 (FIG. 4) extended through a mounting plate 54 formed on the units 52.Each supporting unit 52, FIGS. 1,3 and 4-, includes four uprightuniformly spaced plates 56 having provision for supporting a pair ofparallel shafts 58 extended laterally thereof. The unit 52 for thehousing 44 carries a pair of shafts 58 (FIG. 3) which are spaced apartin a direction longitudinally of the tractor 21 for supportingcorresponding sheaves which are likewise spaced longitudinally of thetractor. The unit 52 for the housing d4 supports three sheaves 60, 64and 66, as indicated diagrammatically in FIG. 6, corresponding to andpositioned within the three sheave chambers 62 formed between the plates56. The sheave 69 is supported on the rear one of the shafts 53 and thesheaves 64 and 66 are supported side by side on the forward shaft 53.

The sheave-supporting unit 52 for the housing 42 has only a single shaft58, corresponding to the forward shaft in the unit 52 for the housing'44. The unit 52 for the housing 42 has a rear opening for a shaft 58only for the purpose of maintaining the sheave-supporting units 52 of auniform character so that they are interchangeable on the housings 42and 4 A pair of sheaves, 68 and 76', and a cable anchor block 72, aresupported on the single shaft 53 and are separated by the plates 56 inthe supporting unit 52.

A pair of sheave-supporting units 74, only one of which is shown,corresponding to the units 52, are carried on a rearwardly projectingsupport 76 (FIG. 2) provided on the dozer blade 34. Each unit 74includes a transverse sheave-supporting shaft 78 and is pivotallymounted on the support 76 by means of a universal joint assembly 80which provides for tilting of the unit 74 in response to tilting of theblade 34 in a direction transversely of the tractor 71. In eachuniversal joint assembly 86, the support 76 carries a socket 79 (HG. 7)for a semi-ball shape head 8 1 on one end of a bolt 83, the opposite endof which is secured by a nut 85 to the unit 74. A spring 87 encirclesthe bolt 83 and extends between the unit 74 and the support 76 forresiliently holding the unit 74 away from the support '76. A pair ofsheaves $2 and 84 are mounted in a side-by-side relation on the shaft 78for each of the units 74.

With reference to FIG. 6, a single cable 86 has one of its ends securedto the block 72 carried by the sheavesupporting unit 52 for the tractorsection 24. The cable 56 is then trained successively about the sheaves84, 7t), 82 and 68. From the sheave 68, the cable 86 extends downwardlyand is trained about a sheave 88 rotatably supported on a shaft 90extended longitudinally of the tractor section 24. The shaft 96 issupported on a front housing section 43 which is bolted to the main part46 of the housing 42. The cable 86 extends transversely of the tractorfrom the sheave 88 to a corresponding sheave 92 similarly secured to afront section 48 for the housing 44 for rotation about a shaft 94extended longitudinally of the tractor section 22. The cable 86 thenextends upwardly and is successively trained about the sheaves 66, 84,64, 32 and 60. From the sheave 66, the cable 86 extends downwardly andis wound about and secured to a drum 96 which forms a part of a powertransmission mechanism 98 (FIG. 5), the moving parts of which areenclosed within the housing 44.

It is to be noted that the only function purpose for the housingsections 48 is to support the sheaves 88' and which are required totransfer the cable 36 from one tractor section to the other in thetwin-type tractor illustrated so that the weight of the blade 34 isdivided between the tractor sections 22 and 24. In an installation ofthe control unit 29 on a conventional single engine tractor only asingle housing part 46 can be used and the front part 48 therefor can beeliminated to conserve space between the tractor and the dozer blade, ifdesired. in a cable control unit on a single-engine tractor only oneupper sheave supporting unit 52 is used since only a. single housing ornose guard 44 is required, and only one sheave-supporting unit 74 isused on the dozer blade. In such case, the cable 86 is trained about thesheaves in substantially the manner illustrated in the right handportion of PEG. 6, with an anchor block 72 being substituted for thesheave 66 and the cable 86 terminating at the anchor block. It isapparent that finer adjustments of the dozer blade may be obtained byusing a longer cable 36 and using additional upper sheaves like thesheave 64 and additional lower sheaves like the sheaves 84.

As best appears in FIG. 3, the drum 96 extends rearwardly from a gearcasing *lfilti which is mounted on the front open end of the main part46 for the housing 44. As shown in FEGS. 3 and 4, the casing 16 Gextends completely across the open front end of the housing part 46 sothat it functions as a cover for the part 46, and is connected to aninwardly extending flange 1% (FIGS. 3, 4 and 5) on the part 46 by bolts101. The mechanism $8 is driven from a power input shaft 104 which is inturn driven from the engine 29 corresponding to the housing 44. Theshaft 164 is releasably connected to and drives a gear 166 within thecasing 102 which in turn operates through a second gear 168 to drive alarger gear 116 connected to the front end of a floating shaft 112extended longitudinally of the tractor 21.

The shaft 112 carries a sun gear 115 arranged in meshing engagement withseveral planet gears 114 (only one of which is shown) which are mountedon pivots 116 on a planet carrier frame 113. As best appears in FlG. 5,the frame 118 has a forwardly extending tubular portion 11) positionedabout the shaft 112 and supported on a bearing 12% on the casing 160.The frame 113 also has a rearwardly directed cylindrical portion 127aligned with the shaft 112 and supported on a bearing 127a. The drum 96is mounted on a bearing 1211b carried by the cylindrical portion 119 ofthe carrier frame 118 and, as will more clearly appear hereinafter, on abearing 123 positioned about the frame portion 127. The drum 6 issecured by means of bolts 122 to a ring gear 124 which meshes with theplanets 114 and carries an encircling brake drum 126. An annularinwardly and rearwardly extending disk 121 attached to the gear 124 bythe bolts 122, and thus connected to the drum 96, is rotatably supportedon the bearing 123 extending about the cylindrical carrier portion 127which has a frontend section 123 which serves as a thrust support forthe rear end of the shaft 112. A tube 125 secured to the carrier portion127 carries an outwardly extended disk 129 which in turn supports anencircling drum 130 arranged adjacent and in a coaxial relation with thedmrn 126. The drums 126 and 130 are hereinafter referred to as the brakedrum and the clutch drum, respectively.

For operating the mechanism 98, a brake band 132 and a clutch band 13 i,corresponding to the drums 126 and 136 are arranged in an encirclingrelation with the drums 126 and 135i, respectively.

The bands 132 and 134 are similar in construction and, as best appearsin FIG. 8, each is formed in two sections 136 and 132i, pivotallyconnected at their upper ends by a pivot member 14d and connected attheir lower ends to a corresponding pair of links 142 and 144. The link1 42 is connected by means of another link 146a and a bolt 146 to thehousing 44. The link 1144 is of a bifurcated construction having legsarranged on opposite sides of the link 142. The link 144 for the clutchband 134 is connected by means of a rod 148 to an car 149 mounted on asleeve 15?: which is secured to a shaft 152 mounted on trunuions 153secured to the housing 44 and arranged to one side of the mechanism 93.On rotation of the shaft 152 in a clockwise direction as viewed in FIG.8, the band 134 is tightened about the drum 130.

The link 144 for the brake band 132 is coimected by another link 1531 toan car 154 formed on a sleeve 156 rotatably supported on the shaft 152.A second car 158 secured to the sleeve 156 is connected to the lower endof a bolt 160 which carries a spring 162 arranged in compression betweena mounting bracket 164 on the housing 44 and a washer 166 positioned onthe bolt at the upper end thereof. Thus, the spring 162 operates tocontinually maintain the brake band 132 in holding engagement with thebrake drum 126. A sleeve 168 fixed on the front end of the shaft 152carries a lever 169 connected to the lower end of an upright rod 170which is in turn connected at its upper end to an arm 172 mounted on ashaft 173 rotatably supported by the rousing 44.

A second arm 174 carried by the shaft 173 is adapted to be connected toa manual or power operated mechanism (not shown) for moving the rod 17%up or down as desired. A counterclockwise rotation of the arm 172,whether effected by power or manually operated means, is effective toraise the rod 176) to in turn rotate the shaft 152 to tighten the clutchband 134 about the clutch drum 135 and hold the drum 136- againstrotation.

When the clutch drum 13% is held in a stationary position by the band134, the planet carrier 1.18 is held so that the pivots 116 function asfixed pivots for the gears 114. As a result, the rotating shaft 112 iseffective to rotate the planet gears 11d, and in turn the ring gear 124in a counterclockwise direction when viewed from the front of thetractor to in turn rotate the drum 96 and raise the dozer blade 34.Whenever the operating force on the arm 172 is discontinued, a spring(not shown) associated with the band 134 provides for an expansion ofthe band 134 so that rotation of the drum 96 to raise the dozer blade 34is discontinued.

it is to be noted that during raising of the dozer blade 34, theapplication of the brake band 132 to the brake drum 126 is notdiscontinued. A release of the pressure of the band on the brake drum12s is not necessary since, as best appears in FIG. 8, the frictionalforce of the drum 126 on the band 132 is in a direction corresponding tothe direction of rotation of the drum 126 and opposite to the directionof application of the force which applies the band 132, namely, theforce exerted by the spring 162. As a result, the total force exerted bythe band 132 on the drum 12,6 resisting drum rotation is at a minimum.Accordingly, it is not necessary to discontinue this brake force on thebrake drum 126 during raising of the blade 3 3.

On the contrary, when the drum 96 for the cable 86 is rotated in adirection for lowering the dozer blade 34, namely, clockwise as viewedfrom the front of the tractor, the frictional force of the drum 126 onthe band 132 is in a direction corresponding to the direction of theoperating force on the band 132 so that the frictional band force on thedrum 12o increases as the torque on the 6 drum 126 is increased with theresult that rotation of the drum 126 is restrained.

It can thus be seen that once raising movement of the dozer blade 34 isdiscontinued, the brake band 132 operates automatically and immediatelyto prevent any accidental lowering of the blade 34 and to maintain theblade at a moved position.

To lower the blade, the arm 174 is rotated in an opposite direction torotate the shaft 152 in a counterclockwise direction as viewed in FIG.8. In response to such rotation, the ear 149 on the sleeve 150 engagesan overlapping stop 176 on the sleeve 156. The stop 176 overlaps thesleeve 150 so as to be in the path of the car 149 to provide for aconcurrent rotation of the sleeve 156 and the ear 154 to discontinue theforce of the brake band 132 on the brake drum 126. Consequently, boththe bands 132 and 134 are released so that the drum 96 and the ring gear124 are free to rotate in response to lowering of the blade 34 under theaction of its own weight.

It is to be understood that any operative structure can be provided forapplying the brake and clutch bands 132 and 134 as required to effectthe desired rotation or holding of the drum 96, the lever mechansirnpreviously described being only an illustrated form of a preferredstructure. In any event, the housing 44 is formed so that the bandoperating structure is readily applied thereto and removed therefrom.The trunnions 153, bracket 164 and the supporting plates or brackets forthe shift 173 are mounted on bolt pads provided on the housing so thatthese parts can readily be attached thereto.

It can thus be seen that the mechanism 98 is readily operable to providefor rotation of the drum 96, which with its associated operatingstructure constitutes a winch, to thus provide in turn for a selectiveraising and lowering of the dozer blade 34. By virtue of the mounting ofthe housings 42 and 44 on the engine supporting tractor frame portions26a, the unit 20 may be quickly assembled with the tractor 21 at aposition to avoid interference from dirt, rocks and the like, which maypile up at the front end of the tractor. Furthermore, the casing and thehollow housing part 46 cooperate to completely enclose the moving partsof the mechanism 98, which are subject to clogging with dirt and thelike, and function as a nose guard for the tractor.

The disposition of the sheaves on the supporting units 52 in planesextended longitudinally of the tractor provides for a minimum ofinterference of the sheaves with the tractor operators vision. The unit20 is readily installed in the field since it is only necessary to mountthe two housings 42 and 44 and the two sheave-supporting units '74 onthe tractor and the blade, respectively. The arrangement of the housingsso that they are mounted by means of the releasable pins 51 carried bythe mounting plates St} further simplifies the assembly of the housingswith the tractor 21. The power transmission mechanism is readily removedas a unit from the housing support 46 by merely removing the bolts 101,moving the bands 132 and 134 out of engagement with the drums 126 and13b, and moving the mechanism forwardly out of the housing 46. Onceremoved, it is just as quickly replaced by re-inserting the bolts and byvirtue of its pro-assembled construction can be repaired and tested inthe shop or factory. If removal of the actuating structure for the powertransmission mechanism, which consists of the bands 132 and 134 andtheir operating structure is desired, for example, when replacting theunit 20 with a hydraulic unit to be hereinafter described, the trunnions153, the bracket 164 and the supporting-plates for the shaft 173 aredetached from their bolt pads and removed.

A second form of the control unit of this invention indicated generallyat 206, is illustrated in FIG. 11 mounted on the tractor 21. The unit 2Wincludes a pair of housings 262 and 203 identical to the correspondinghousings 42 and 44 used in the control unit 29. The

a housings 202 and 223 are provided on their top sides with a pair ofcorresponding brackets 204, (only one of which is shown in FIG. 11),releasably connected to the housings by means of bolts 2% and havingforwardly projected upright plate portions 2% (FIG. 14) arrangedforwardly of and above the housings 202 and 223. The plate portions 298are spaced apart, in a direction transvcrsely of the tractor 21, adistance to receive therebetween a cylinder 21%) for a hydrauliccylinder and piston assembly, indicated generally at 212. As willclearly appear hereinafter, in this embodiment of the invention thefront part, corresponding to the parts 48 in the unit 2%, of each of thehousings 2%2 and 2% serves no functional purpose and is readily omittedif additional space is required between the tractor front end and theblade 34a.

The cylinder 2% has stub shafts secured thereto and positioned in aplane extended substantially longitudinally of the tractor. A pair ofcastings 216, of complementary shapes, have cooperating yoke portions218 which straddle transversely opposite sides of the cylinder and arereleasably connected by bolts 22% arranged on opposite sides of thecylinder for moving diagonally inclined meeting faces 222 on thecastings are into abutting engagement. When connected, the castings 216form bearing supports for rotatably supporting the shafts 214 on thecylinder 21d. The castings 2% are provided with corresponding stubshafts 226 which are axially aligned in the connected position of thecastings and positioned substantially perpendicular to the shafts 21.4in a plane extended substantially transversely of the tractor 21.

Each of the stub shafts 226 is rotatably supported in an annular bushing230 having a spherical outer surface 232 and supported in acomplementary spherical inner surface 234 formed on a bearing sleeve asssupported in a cavity 237 in the corresponding plate portion 2%. lnmounting the cylinder 21%, the castings are are first manipulated sothat the stub shafts 226 are rotatably supported within the bushings 23%following which the castings 216 are bolted together. The castiigs 21%cooperate with the stub shafts 214 to provide a gimbal-type support forthe cylinder 21%. In other words, the cylinder 21th is readily rotatableabout the axis of the stub shafts 226 on raising and lowering of thedozer blade 3412, as illustrated in FIG. 11, and is readily rotatableabout the axis of the stub shafts 214 in response to de fiection of theblade 34a in a direction transversely of the tractor in response toload. It is apparent that the loads applied to the blade 34a are seldomuniformly distributed along the blade and as a result, some sidedeflection of the blade is inevitable. In response to such deflection,the cylinder 21!} merely pivots about the shafts 214 so as not to undulystrain any of the structural parts of the blade 34a, its supportingstructure or the cylinder assembly 212.

During relative up and down movement of the tractor sections 22 and 24,the bushings 230 readily tilt with respect to the sleeves 236 by virtueof the complementary curved surfaces 232 and 234 so as not to preventthe desired relative movement of the parts. Furthermore, the distancebetween the plate portions 2% increases and decreases and the stub shaft226 for the housing 262 merely slides in its bushing 23s when thisdistance changes. A shoulder 239 provided on the terminal end of thestub shaft 226 corresponding to the housing 293 prevents accidentalmovement of the stub shaft 22%? out of its bushing 230.

During the shipment of the tractor 2 1 in the separate sections 22 and24, which is required because of the size of the tractor 21, theattachment 2% is readily maintained intact on the section 22 having thehousing 2%. Since the power transmitting mechanism for the unit 2% isalso supported on the housing 203, in a manner hereinafter described,when the sections 22 and 24 are connected after shipment, no hydraulicconnections are required.

The piston and cylinder assembly 212 includes the usual piston rod 240which is pivotally connected at its lower end to a plate 242 provided onthe rear end of the dozer blade 34a. As a result, on retraction of thepiston rod 240 relative to the cylinder 219, the blade 34a is readilyraised relative to the tractor 2-1. Conversely, on extension of thepiston rod 249, the blade 34a is lowered as shown in FIG. 11.

It is seen, therefore, that in response to actuation of the singlehydraulic cylinder and piston assembly 212 the dozer blade 34a isreadily raised and lowered as desired. For actuating the assembly 212, apower transmitting mechanism consisting of a hydraulic, pump, tank andvalve assembly 244 (FIGS. 12 and 15) is mounted in the housing 293 andextends downwardly through an opening 2% in the front housing part. Theassembly 244 includes a tank 246 having a front cover plate 248a whichconstitutes the front side of the tank 246 and is connected thereto by.bolts 247a. A series of bolts 247 connect the cover plate 24$a to anannular inwardly directed flange 249 on the housing 203, similar to thecorresponding flange 103 on the housing 44. The cover plate 2-t3a thuscloses the open front end of the main housing part and provides foromission of the housing front part if desired.

An adapter casting mounted on the cover plate 248a by bolts 2 i7acarries a pump 25ft, which may be of gear type, arranged in a drivenrelation with the engine operated shaft 124 described in connection withthe unit 29. The pump 256 has an intake passage 252 (FIG. 12)communicates with the tank 246 at a position below an inclined bafiie254 mounted in the tank. An outlet passage 256 for the pump 250communicates at its upper end with a spool type valve, of well knowntype, indicated generally at 258, above the bafile 254.

The valve 258 controls the supply of fluid under pressure to a pair offlexible fluid lines 26% and 262 which communicate with the upper andlower ends, respectively, of the cylinder 21% on opposite sides of thepiston (not shown) in the cylinder. An upright control shaft 264- forthe valve 253 is rotatably supported at its lower end in a bracket 266on the adapter casting 248 and is operable on rotation to move the valve253 between the various operating positions therefor.

As illustrated in FIG. 16, the valve 253 is movable between what arehereinafter termed float, lower, hold and raise positions, whichpositions are defined by the position of a plate 27% secured to thecontrol shaft 264 and extended rearwardly therefrom. The plate 27% ispivotally connected to a spool control member 272 which in turn movesthe valve 258 between the control positions thereof. The rear orterminal end 274 of the plate 270 is of an irregular shape and acts as acam sur face which cooperates with a cam follower or roller 275 todefine the control positions of the shaft 264.

As best appears in FIG. 16, the follower 276 is mounted on one end of arod 278 which is pivotally supported at its opposite end at 280 on anear 282 secured to the adapter casting 248. A spring 284 extends betweenthe rod 273 and the casting 248 for resiliently maintaining the follower276 in engagement with the cam surface 274, which is formed with tworearwardly diverging portions 285 so that it has an intermediate point286 between tween the portion 285 which is termed the low point on thesurface 274. When the follower 276 is opposite the low point 286, thevalve 258 is in its hold position preventing fluid flow in either of thelines 260 or 262. It is apparent that the spring 284 provides for anautomatic movement of the plate 270 to this position when the operatingforce on the control shaft 254 is discontinued.

To maintain the valve 253 in either a raise or a lower position, inwhich positions the follower 276 i on opposite sides of the low point286, a continued operating force must be maintained on the control rod264. To move the control rod 258 into a float position in which nopressure is applied through either of the lines 260 and 262, so that theblade 34a is free to move up and down, the plate 276 must be moved to aposition in which the follower 276 is within a pocket 288 at one end ofthe cam surface 274. In order to move the plate 270 to this position,the follower 276 must first travel over a projection 290 formed on thecam surface 274 adjacent the pocket 283. Thus, the projection 29%imparts feel to the operator to indicate that the float position of thevalve 258 is being approached. An arm 292 secured to the upper end ofthe control shaft 264 is preferably linked by a connecting structure294, which is only partially shown, to an operating lever adjacent theoperators seat on the tractor 21 so that the valve 258 can beconveniently operated.

In the operation of the tractor 21 with the control unit Zilii, thedozer blade 34a is normally maintained at a desired position to which ithas been previously moved by automatically maintaining the valve 258 inthe hold position. To raise the blade 340, the control rod 264- isrotated in one direction to move the valve 258 to a position in whichfluid under pressure is supplied to the line 262 and fluid is exhaustedfrom the line 260 to the tank 246 at a position above the baffle 254-.By virtue of this discharge of fluid above the baffle 254, theturbulence of the fluid is not transmitted to the fluid which issupplied to the pump intake 252 below the baflle 25 5. When raisingmovement of the blade 34a is to be discontinued, the operating force onthe control rod 264 is discontinued so that the valve automaticallymoves to the hold position corresponding to a position of the camfollower 276 opposite the low point 236 on the cam face 274. To lowerthe blade 34-, the control rod 264 is rotated in a reverse direction sothat the fluid under pressure is supplied through the line 269 to thecylinder 210. On movement of the plate 270 past the lower position to afloat position, no pressure is supplied through either of the lines 260and 262 so that the blade 34a is free to move up and down with thecontour of the ground. Such a blade control is used, for example, duringback filling operations with the tractor 21.

The previously enumerated advantages for the unit 24 are equallyapplicable to the unit 200, which is also readily installed as a packageeither in the field or at the factory by virtue of the construction ofthe housing 253 and the power transmission mechanism 244 for readyassembly. It is only necessary to mount the housings 262 and 203 whichis readily accomplished with mounting plates and pins like the plates 5dand pins 51 previously described, and connect the piston rod 24! to thedozer blade 34a. Furthermore, by virtue of the gimbal-type mounting forthe hydraulic cylinder assembly 212, any up and down tilting or sidewaysdeflection of the blade 34a does not interfere with the properfunctioning of the assembly. The location of the valve 258 and all ofthe circuitry for the hydraulic system in the casting 248 eliminatesfield connections and makes replacement of this structure relativelyeasy from an assembly standpoint. All of this structure is combined in asingle bench assembly which can be tested at the plant.

As a result of the mounting of the housings 262 and 203 and the factthat they are identical with the housings 42 and 44 in the unit 20, ahydraulic control unit 2&0 is readily converted to a cable control unit29 and vice versa. The bolt patterns on the main portions of thehousings 44 and 293 for receiving the mounting bolts 101 and 247 are thesame so that either type unit is readily mounted on a housing. Further,the openings 102 and 205 are substantially the same so that the housingfront parts, when they are used, do not interfere with theinterchangeability of the control units. When the front parts areomitted, the sheave supporting units 52 and brackets 294 arecantilever-supported on the main housing parts. As previously pointedout, the units 253 and 2% have for convenience been particularlydescribed only with respect to their assembly with the twin-type tractor21, and both units are readily adapted to the conventional tractorhaving a single main frame and a single engine. In a hydraulic controlunit on a single-engine tractor both of the supporting brackets 204 forthe supporting shafts 226 on the cylinder 216) are supported on thesingle housing 2% which is used.

Although the invention has been described with respect to a preferredembodiment thereof, it is to be understood that it is not to be solimited, since changes can be made therein which are within the scope ofthe invention as defined by the appended claims.

What is claimed is:

1. In combination with a tractor having a main frame, propelling en inemeans on said frame adjacent the front end thereof, and a Workattachment movably mounted on the tractor forwardly thereof, a housinghaving an open front end mounted on said main frame at the same leveland forwardly of said engine means, said housing including means thereonadapting the housing for detachably supporting power output means formoving said work attachment, means on the front end of said housing fordetachably supporting a power transmission mechanism connectible to saidengine means and said output means to operate the output means, and apre-assembled power transmission mechanism having a front cover portionreleasably mounted on said housing means so as to substantially closesaid housing when said mechanism is disposed therein.

2. A power control unit for a tractor having a main frame, an enginemounted on a portion of said frame and a work attachment movably mountedon said tractor, said unit comprising housing means mounted on saidtractor frame portion adjacent said engine, a hydraulic piston andcylinder assembly pivotally mounted on said tractor for swingingmovement about an axis extending transversely of the tractor, meansoperatively connecting said hydraulic assembly and said work attachmentto provide for raising and lowering of said attachment in response toactuation of said assembly, and a pre-assembled hydraulic pump, valveand tank mechanism detachably supported on and substantially enclosedwithin said housing means for operation by said engine to actuate saidhydraulic cylinder assembly.

3. In combination with a tractor having a main frame, propelling enginemeans on said frame, and a work attachment movably mounted on thetractor, a housing mounted on said main frame, a hydraulic piston andcylinder assembly movably mounted on said tractor and connected to saidwork attachment, said assembly having a piston rod and being operable tomove said attachment in opposite directions on extension and retractionof said piston rod, a pre-assembled power transmission unit comprising atank positioned in said housing and having a supporting plate removablymounted on said housing, a pump supported on said plate in communicationwith said tank and connected to said engine for driving thereby, controlvalve means supported on said plate and connected to said pump and saidcylinder and communicating with said tank, and fluid passage meansformed in said plate for fluid communicating said valve, tank and plate.

4. For use with a tractor having a main frame, propelling engine meanson said frame, and a work attachment movably mounted on said frame,housing means mounted on said main frame at a position horizontallyadjacent said engine means, a pre-assembled control valve, pump and tankunit removably mounted on said housing means and connected to the enginemeans for operation of the pump thereby, hydraulic cylinder and pistonmeans mounted on said housin means and connected to said valve foroperation in response to actuation of said assembly, and means forconnecting said hydraulic cylinder and piston means to said workattachment for moving the attachment.

5. For use with a twin-type tractor having a pair of are 1,?79

pivotally connected side by side frames, each of which has propellingengine means mounted thereon adjacent the front of said tractor, a powercontrol unit mounted on the tractor for raising and lowering workattachments for said tractor, said unit including a pair of housingmembers mounted on said frames at positions forwardly of said enginemeans, a mounting flange on the front end of one of said housingmembers, a pro-assembled power transmission unit having a cover portionremovably supported on said flange so as to substantially close said onehousing, said transmission unit being connected to one of said enginemeans for operation thereby, and power output means mounted on saidhousings and operatively associated with said power transmission meansfor operation in response to operation of said transmission means.

6. In combination with a tractor havin a main frame, propelling enginemeans on said frame adjacent the front end thereof, and a workattachment movably mounted on the tractor forwardly thereof, a housinghaving an open front end mounted on said main frame forwardly of saidengine means, a pro-assembled power transmission unit extending withinsaid housing, said unit having a front cover portion removably connectedto the front end of said housing so as to substantially close thehousing, said unit comprising winch means mounted on said cover portionand disposed within said housing, means connected to said winch meansand said engine for driving the winch means in one direction, firstsheave means removably mounted on said housing, second sheave meansmounted on said work attachment, and a cable wound about said winchmeans and said first andv second sheave means for raising said workattachment on movement of said winch means in said one direction.

7. In combination with a twin-type tractor having a pair of pivotallyconnected side by side main frames, propelling engine means mounted onsaid frames adjacent the front ends thereof, and a tractor workattachment movably mounted on said frames at a position forwardlythereof, a pair of housings mounted on said main frame forwardly of saidengine means, a hydraulic piston and cylinder assembly having a cylinderand a piston rod connected to said work attachment, means on saidcylinder providing a pair of stub shafts projecting from transverselyopposite sides thereof, co-acting ball and socket means on said stubshafts and said housings providing for a movable support of the stubshafts on the housings so that the ball and socket means are movable inresponse to relative up and down movement of said tractor frames tomaintain the cylinder in a predetermined position, one of said stubshafts being mounted for sliding movement relative to its correspondingball and socket means, and a power transmission unit supported on one ofsaid housings and connected to said hydraulic cylinder assembly forretracting and extending said piston rod to raise and lower said workattachment.

8. In combination with a tractor having a main frame, propelling enginemeans mounted on said main frame adjacent the front end thereof, and awork attachment movably mounted on the tractor forwardly thereof, ahousing mounted on said main frame forwardly of said engine means, saidhousing including means on the upper end thereof adapting said housingfor supporting a sheave unit, a rare-assembled power transmission unitreleasably mounted on and extended within said housing, said unitcomprising winch means disposed in said housing, means connected to saidengine and operatvely associated with said winch means for driving thewinch means in one direction, sheave means on said work attachment, acable trained about said winch means, said sheave unit and said sheavemeans for raising the work attachment on rotation of said winch means insaid one direction, brake band means in said housing engageable with aportion of said winch means for holding the winch means in a rotatedposition, said band means being movable to a position in a clearancerelation with said unit when said unit is to be removed from thehousing.

References Qited in the file of this patent UNITED STATES PATENTS2,529,299 LeTourneau Nov; 7, 1950 2,678,105 Peterson May 11, 19542,682,717 LeTourneau July 6, 1954 2,765,536 Perkins Oct. 16, 19562,787,065 Bock et al. Apr. 2, 1957 2,921,392 Bidwell Ian. 19, 1960FOREIGN PATENTS 654,273 Great Britain Oct. 25, 195.0

UNITED STATES PA CERTIFICATE OF TENT OFFICE CORRECTION Patent No.

May 1, 1962 Joseph M. Gwinn It is hereb y certified that error appe entrequiring are in the above nu correction and that the said Letters Pcorrected below.

Jr.,, et al a mbered patatent should read as Column 4, line 10, for"function" column 6, line 28, for "shift" "replacting" read rep column 7out "the", first occurrence; column 8 "communicates" insert w "tween"line 64 column 1 line 44 "654,273" read 645 line 66 for ine 67, strike gbefore strike out n patent number lacin CRNEST W. SWIDER DAVID L. LADDttesting Officer Commissioner of Patents

